JP6393781B2 - Excavator - Google Patents

Description

  The present invention relates to an excavator equipped with a turbocharged diesel engine.

  There is known an excavator that performs power generation by a generator connected to an engine before the hydraulic load of a hydraulic pump connected to a turbocharged diesel engine increases (see Patent Document 1). This excavator actively increases the power generation load before the hydraulic load increases to increase the engine load and therefore the supercharging pressure, so that even if the hydraulic load suddenly increases thereafter, the engine speed is almost constant. The engine output can be increased smoothly while maintaining the above. Hereinafter, the function of increasing the supercharging pressure by executing power generation by the generator before the hydraulic load increases is referred to as “pre-load boost function”.

International Publication No. 2012/169558

  However, if the hydraulic load does not increase rapidly after executing the pre-load boost function, the increase in supercharging pressure due to the execution of the pre-load boost function may be wasted.

  In view of the above, it is desirable to provide an excavator that performs the pre-load boost function more efficiently.

  An excavator according to an embodiment of the present invention includes an attachment including a working body, a diesel engine with a supercharger, a hydraulic pump connected to the diesel engine with a supercharger, and before the hydraulic load of the hydraulic pump increases. And a controller that executes a pre-load boost function for increasing the supercharging pressure of the supercharger, and a region where the predetermined part of the attachment is reachable is when the work body is operated before the load A partial region where the boost function is executed and a partial region where the pre-load boost function is not executed when the work body is operated.

  The above-described means provides a shovel that performs the pre-load boost function more efficiently.

It is a side view of the shovel which concerns on the Example of this invention. It is a figure which shows the structural example of the drive system of the shovel of FIG. It is a functional block diagram which shows the structural example of the controller mounted in the shovel of FIG. It is a figure explaining the process which derives the position of each point on an excavation attachment. It is a figure explaining the process which derives the position of each point on an excavation attachment. It is a side view of the shovel showing an actual work area. It is a figure which shows an example of the relationship between a bucket pin distance and the electric power generation amount per unit time. It is a flowchart which shows an example of the flow of the pre-load boost necessity determination process. It is a side view of the shovel showing an actual work area. It is a time chart which shows the time transition of lever operation amount, electric power generation amount, hydraulic load, fuel consumption, supercharging pressure, and engine speed.

  Initially, with reference to FIG. 1, the whole structure of the construction machine based on the Example of this invention is demonstrated. FIG. 1 is a side view showing a configuration example of an excavator as a construction machine according to an embodiment of the present invention. However, the present invention is not limited to the excavator, and can be applied to other construction machines as long as it is equipped with a turbocharged diesel engine.

  An upper swing body 3 is mounted on a lower traveling body 1 of the shovel shown in FIG. A boom 4 as a working body is attached to the upper swing body 3. An arm 5 as a working body is attached to the tip of the boom 4, and a working body and a bucket 6 as an end attachment are attached to the tip of the arm 5. Note that the end attachment may be a breaker, a grapple, or the like.

  The boom 4, the arm 5, and the bucket 6 constitute an excavation attachment that is an example of an attachment, and are hydraulically driven by the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9, respectively. A boom angle sensor S1 is attached to the boom 4, an arm angle sensor S2 is attached to the arm 5, and a bucket angle sensor S3 is attached to the bucket 6.

  The boom angle sensor S <b> 1 is an example of a posture detection device that detects the posture of the excavation attachment, and detects the rotation angle of the boom 4. In the present embodiment, the potentiometer detects an inclination angle of the boom 4 with respect to a horizontal plane (hereinafter referred to as “boom angle”). Specifically, the boom angle sensor S1 detects the rotation angle of the boom 4 around the boom foot pin connecting the upper swing body 3 and the boom 4 as the boom angle.

  The arm angle sensor S <b> 2 is an example of a posture detection device that detects the posture of the excavation attachment, and detects the rotation angle of the arm 5. In the present embodiment, the potentiometer detects an inclination angle of the arm 5 with respect to the horizontal plane (hereinafter referred to as “arm angle”). Specifically, the arm angle sensor S2 detects the rotation angle of the arm 5 around the arm pin that connects the boom 4 and the arm 5 as the arm angle.

  The bucket angle sensor S3 is an example of a posture detection device that detects the posture of the excavation attachment, and detects the rotation angle of the bucket 6. In this embodiment, the potentiometer detects the inclination angle of the bucket 6 with respect to the horizontal plane (hereinafter referred to as “bucket angle”). Specifically, the bucket angle sensor S3 detects the rotation angle of the bucket 6 around the bucket pin (arm top pin) connecting the arm 5 and the bucket 6 as the bucket angle.

  Note that at least one of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3 is an acceleration sensor, a stroke sensor that detects the stroke amount of the corresponding hydraulic cylinder, and a rotary that detects the rotation angle around the connecting pin. An encoder or the like may be used.

  FIG. 2 is a diagram showing a configuration example of the drive system of the shovel shown in FIG. In FIG. 2, the mechanical power system is indicated by a double line, the high-pressure hydraulic line is indicated by a thick solid line, the pilot line is indicated by a broken line, and the electric drive / control system is indicated by a thin solid line.

  The engine 11 is a shovel drive source. In this embodiment, the engine 11 is a diesel engine including a turbocharger as a supercharger and a fuel injection device, and is mounted on the upper swing body 3. The engine 11 may include a supercharger as a supercharger. The engine 11 employs isochronous control that keeps the engine speed constant regardless of increase or decrease in engine load.

  The motor generator 12 is a device that functions as an electric motor and a generator. In the present embodiment, the motor generator 12 functions as an electric motor that assists in driving the engine 11 and also functions as a generator that generates electric power using the driving force of the engine 11.

  The engine 11 and the motor generator 12 are connected to two input shafts of the speed reducer 13, respectively. A main pump 14 and a pilot pump 15 are connected to the output shaft of the speed reducer 13. A control valve 17 is connected to the main pump 14 via a high pressure hydraulic line 16. An operation device 26 is connected to the pilot pump 15 via a pilot line 25.

  The main pump 14 is a variable displacement swash plate hydraulic pump that can vary the discharge amount (retraction volume) per rotation. The discharge amount per rotation is controlled by a pump regulator. The rotation shaft of the main pump 14 is connected to the rotation shaft of the engine 11 and rotates at the same rotation speed as the rotation speed of the engine 11. The rotation shaft of the main pump 14 is connected to the flywheel. This is to suppress fluctuations in the rotation speed when the engine output torque fluctuates.

  The control valve 17 is a hydraulic control device that controls a hydraulic system in the shovel. In the present embodiment, the control valve 17 is connected to various hydraulic actuators such as the right traveling hydraulic motor 2A, the left traveling hydraulic motor 2B, the boom cylinder 7, the arm cylinder 8, and the bucket cylinder 9 through a high pressure hydraulic line.

  The inverter 18 controls the operation of the motor generator 12. In the present embodiment, the inverter 18 is provided between the motor generator 12 and the power storage device 120, and controls the operation of the motor generator 12 based on a command from the controller 30. Specifically, the inverter 18 supplies necessary power from the power storage device 120 to the motor generator 12 when the motor generator 12 is controlled as a motor. In addition, the inverter 18 stores the electric power generated by the motor generator 12 in the power storage device 120 when the motor generator 12 is controlled as a generator.

  The inverter 20 controls the operation of the turning electric motor 21. In this embodiment, the inverter 20 is provided between the turning electric motor 21 and the power storage device 120, and controls the operation of the turning electric motor 21 based on a command from the controller 30. Specifically, the inverter 20 supplies necessary electric power from the power storage device 120 to the turning electric motor 21 when the turning electric motor 21 is controlled as an electric motor. Further, when the turning electric motor 21 is controlled as a generator, the inverter 20 stores the electric power generated by the turning electric motor 21 in the power storage device 120.

  The turning electric motor 21 is a device that turns the upper turning body 3 with respect to the lower traveling body 1, and functions as an electric motor and a generator like the motor generator 12. In the present embodiment, the turning electric motor 21 functions as an electric motor for turning the upper turning body 3 and also functions as a generator for generating electric power using the inertia moment of the upper turning body 3. A resolver 22, a mechanical brake 23, and a turning speed reducer 24 are connected to the output shaft 21 </ b> A of the turning electric motor 21.

  Power storage device 120 is disposed between inverter 18 and inverter 20. Thereby, when at least one of the motor generator 12 and the turning electric motor 21 functions as an electric motor, that is, when a power running operation is performed, electric power necessary for the power running operation is supplied. Further, when at least one of them functions as a generator, that is, when a power generation (regeneration) operation is performed, the electric power generated by the power generation (regeneration) operation is stored.

  In the present embodiment, the power storage device 120 includes a capacitor 19, a buck-boost converter 19a, and a DC bus 19b. The capacitor 19 is connected to the motor generator 12 via the step-up / down converter 19 a, the DC bus 19 b, and the inverter 18. The capacitor 19 is connected to the turning electric motor 21 via the step-up / down converter 19a, the DC bus 19b, and the inverter 20. The step-up / down converter 19a is disposed between the capacitor 19 and the DC bus 19b so that the voltage level of the DC bus 19b, which varies according to the operating state of the motor generator 12 and the turning electric motor 21, falls within a certain range. Control to switch between step-up operation and step-down operation is performed. The DC bus 19b is disposed between the step-up / step-down converter 19a and each of the inverter 18 and the inverter 20, and enables electric power to be transferred between the capacitor 19, the motor generator 12, and the turning electric motor 21.

  The operating device 26 is a device for operating various hydraulic actuators. In the present embodiment, the operating device 26 generates a pilot pressure corresponding to the operation content such as the operation amount and the operation direction. The operating device 26 is connected to the control valve 17 via a hydraulic line 27. The control valve 17 moves spool valves (flow rate control valves) corresponding to various hydraulic actuators according to the pilot pressure generated by the operating device 26, and supplies hydraulic oil discharged from the main pump 14 to the various hydraulic actuators. The operating device 26 is connected to a pressure sensor 29 via a hydraulic line 28. The pressure sensor 29 converts the pilot pressure generated by the operating device 26 into an electrical signal, and outputs the converted electrical signal to the controller 30.

  The controller 30 is a control device that performs drive control of the shovel. In this embodiment, the controller 30 is an arithmetic processing unit including a CPU and a storage device. Specifically, the controller 30 realizes various functions by causing the CPU to execute a drive control program stored in the storage device. Various functions include a function for determining whether or not to execute the pre-load boost function.

  Next, the function in which the controller 30 determines whether or not to execute the pre-load boost function will be described with reference to FIG. FIG. 3 is a functional block diagram of the controller 30 and includes functional elements used when determining whether or not to execute the pre-load boost function. In the present embodiment, the controller 30 mainly includes an attachment position acquisition unit 31 and a pre-load boost necessity determination unit 32.

  The attachment position acquisition unit 31 is a functional element that acquires the position of a predetermined part of the attachment. In the present embodiment, the attachment position acquisition unit 31 derives the attitude of the excavation attachment based on the detected values of the boom angle sensor S1, the arm angle sensor S2, and the bucket angle sensor S3. This is because the position of each point on the excavation attachment with respect to the reference position is derived. Each point on the excavation attachment includes the position of the bucket pin, the tip position of the bucket 6, and the like. The reference position is a position serving as a reference when deriving the position of each point on the excavation attachment, and is, for example, one point on the turning axis, the front end position of the cabin, the center position of the driver's seat, and the like. In this embodiment, the reference position is the intersection of the pivot axis and the grounding surface of the shovel.

  Here, with reference to FIG. 4A and FIG. 4B, the process which the attachment position acquisition part 31 derives | leads-out the position of each point on a excavation attachment is demonstrated. 4A is a side view of the shovel, and FIG. 4B is a top view of the shovel.

  As shown in FIGS. 4A and 4B, the Z-axis of the XYZ coordinate system, which is a three-dimensional orthogonal coordinate system, corresponds to the pivot axis of the shovel, and the origin O as the reference position is the intersection of the pivot axis and the ground plane of the shovel. Equivalent to.

  Further, the X axis orthogonal to the Z axis extends in the extending direction of the excavation attachment, and the Y axis orthogonal to the Z axis extends in a direction perpendicular to the extending direction of the excavation attachment. The X axis and Y axis rotate around the Z axis as the shovel turns.

  Moreover, as shown to FIG. 4A, the attachment position of the boom 4 with respect to the upper revolving structure 3 is represented by the boom foot pin position P1 which is the position of the boom foot pin as a boom rotating shaft. Similarly, the mounting position of the arm 5 with respect to the boom 4 is represented by an arm pin position P2, which is the position of the arm pin as the arm rotation axis. Moreover, the attachment position of the bucket 6 with respect to the arm 5 is represented by the bucket pin position P3 which is the position of the bucket pin as a bucket rotating shaft. Furthermore, the tip position of the claw 6a of the bucket 6 is represented by a bucket tip position P4.

The length of the line segment SG1 connecting the boom foot pin position P1 and the arm pin position P2 is represented by a predetermined value L ₁ as the boom length, the length of the line segment SG2 connecting the arm pin position P2 and the bucket pin position P3 is represented by a predetermined value L ₂ as arm length, the length of the line segment SG3 connecting the bucket pin position P3 and the bucket tip position P4 is represented by a predetermined value L ₃ as a bucket length. The predetermined values L ₁ , L ₂ and L ₃ are stored in advance in the storage device D4 and the like.

Further, boom angle formed between the line segment SG1 and a horizontal plane is represented by beta _1, arm angle formed between the line segment SG2 and a horizontal plane is represented by beta _2, and the segment SG3 and the horizontal plane The bucket angle formed between is represented by β ₃ . In FIG. 4A, the boom angle β ₁ , arm angle β ₂ , and bucket angle β ₃ are positive in the counterclockwise direction with respect to a line parallel to the X axis.

Here, the three-dimensional coordinates of the boom foot pin position P1 are (X, Y, Z) = (H _0X , 0, H _0Z ), and the three-dimensional coordinates of the bucket tip position P4 are (X, Y, Z) = ( X ₄ , Y ₄ , and Z ₄ ), X ₄ and Z ₄ are represented by Formula (1) and Formula (2), respectively.

なお、Y₄は０となる。バケット先端位置Ｐ４はＸＺ平面上に存在するためである。また、ブームフートピン位置Ｐ１が原点Ｏに対して相対的に不変であるため、ブーム角度β₁が決まればアームピン位置Ｐ２の座標が一意に決まる。同様に、ブーム角度β₁及びアーム角度β₂が決まればバケットピン位置Ｐ３の座標が一意に決まり、ブーム角度β₁、アーム角度β₂、及びバケット角度β₃が決まれば、バケット先端位置Ｐ４の座標が一意に決まる。

Y ₄ is 0. This is because the bucket tip position P4 exists on the XZ plane. Further, since the boom foot pin position P1 is relatively invariant with respect to the origin O, the coordinates of the arm pin position P2 once the boom angle beta ₁ is uniquely determined. Similarly, if the boom angle β ₁ and the arm angle β ₂ are determined, the coordinates of the bucket pin position P3 are uniquely determined. If the boom angle β ₁ , the arm angle β ₂ , and the bucket angle β ₃ are determined, the bucket tip position P4 is changed. Coordinates are uniquely determined.

  In this embodiment, the attachment position acquisition unit 31 derives the coordinates of the bucket pin position P3 with respect to the origin O as the reference position, and outputs the coordinates to the pre-load boost necessity determination unit 32.

  The pre-load boost necessity determination unit 32 is a functional element that determines whether or not to execute the pre-load boost function. In the present embodiment, the pre-load boost necessity determination unit 32 determines whether or not to execute the pre-load boost function based on the bucket pin position P3 when the boom raising operation is performed. Specifically, the pre-load boost necessity determination unit 32 determines whether or not the boom operation lever has been operated in the raising direction based on the output of the pressure sensor 29. When it is determined that the boom operation lever has been operated in the raising direction, it is determined that the boom raising operation has been performed. Note that the pre-load boost necessity determination unit 32 determines that the boom operation lever has been operated in the raising direction when the boom raising operation amount exceeds a predetermined value, for example.

  When it is determined that the boom raising operation has been performed, the pre-load boost necessity determination unit 32 determines whether or not the bucket pin position P3 output from the attachment position acquisition unit 31 is within a predetermined actual work area.

  When it is determined that the bucket pin position P3 is within the actual work area, the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed. On the other hand, when it is determined that the bucket pin position P3 is not within the actual work area, the pre-load boost necessity determination unit 32 determines that it is not necessary to execute the pre-load boost function.

  The “actual work area” is an area set around the excavator. In the present embodiment, the actual work area is set as a partial area within the area where the bucket pin position as the position of the predetermined part of the attachment can be reached. Information about the actual work area is stored in advance in the storage device of the controller 30 or the like. Information about the actual work area may be adjustable via an input device or the like.

  Here, an example of the actual work area will be described with reference to FIG. FIG. 5 is a side view of the excavator and shows the actual work area WA set on the XZ plane. The actual work area WA uses a lower limit line set by using a distance (depth) D (≦ 0) from the ground contact surface of the shovel, and a distance (height) H (≧ 0) from the ground contact surface of the shovel. Upper limit line set, proximal limit line set using distance (proximity) C (≧ 0) from swivel axis SX, and distance (distance) F (≧ C) from swivel axis SX Is delimited by the distal limit line set using. The depth D is, for example, the maximum depth at which the bucket 6 can be visually recognized in a state where the operator of the excavator is seated on the driver's seat. Further, information regarding the actual work area WA such as the depth D, the height H, the proximity C, and the distance F is stored in an adjustable state in the storage device of the controller 30 or the like. Further, the proximity C and the distance F may be set on the basis of other than the turning axis SX, such as the cabin front end position and the driver seat center position.

  When the attachment position acquisition unit 31 derives the bucket pin position P3a, the pre-load boost necessity determination unit 32 determines that the bucket pin position is within the actual work area WA. Then, the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed, and outputs a power generation command to the inverter 18 to cause the motor generator 12 to execute short-time power generation. This is to positively increase the load on the engine 11. In this case, the supercharging pressure increases before the hydraulic load suddenly increases due to the boom raising operation. Therefore, the engine 11 can smoothly increase the engine output while maintaining the rotation speed substantially constant even when the hydraulic load suddenly increases thereafter. This is because the fuel injection amount is not limited due to the low supercharging pressure.

  On the other hand, when the attachment position acquisition unit 31 derives the bucket pin position P3b, P3c, or P3d, the pre-load boost necessity determination unit 32 determines that the bucket pin position is not within the actual work area WA. Then, the pre-load boost necessity determination unit 32 determines that it is not necessary to execute the pre-load boost function, and does not output a power generation command to the inverter 18. This is because if the bucket pin position is not within the actual work area WA, such as when the excavation attachment is greatly extended, it is estimated that the need for a quick boom raising operation is low. For example, when the bucket 6 is deep and the operator of the shovel cannot visually recognize the bucket 6, it is estimated that the operator does not want a quick boom raising operation. Further, when the bucket 6 is at a high place and the operator cannot visually recognize the bucket 6 in a natural posture, it is estimated that the operator does not want a quick boom raising operation. Further, when the bucket 6 is far ahead and the shovel is unstable, it is estimated that the operator does not want a quick boom raising operation. As a result, unnecessary execution of the pre-load boost function can be suppressed, and fuel consumption can be improved.

  The pre-load boost necessity determination unit 32 adjusts the boost pressure realized by executing the pre-load boost function by adjusting the content of power generation by the motor generator 12 when executing the pre-load boost function. May be. For example, the pre-load boost necessity determination unit 32 may change the power generation amount per unit time according to the distance of the bucket pin position to the turning axis SX (hereinafter referred to as “bucket pin distance”). Specifically, the pre-load boost necessity determination unit 32 reduces the power generation amount per unit time as the bucket pin distance increases, and is realized by executing the pre-load boost function as the bucket pin distance increases. You may reduce the magnitude | size of the increase in supercharging pressure. That is, the magnitude of the positive increase of the engine load realized by executing the pre-load boost function may be reduced.

  FIG. 6 is a diagram illustrating an example of the relationship between the bucket pin distance and the power generation amount per unit time. As shown in FIG. 6, the pre-load boost necessity determination unit 32 increases the power generation amount per unit time as the bucket pin distance increases when the boom raising operation is started when the bucket pin position is within the actual work area WA. Is gradually reduced. Specifically, the pre-load boost necessity determination unit 32 sets the power generation amount per unit time to Q1 when the bucket pin distance is not less than D1 and less than D2. When the bucket pin distance is D2 or more and less than D3, the power generation amount per unit time is Q2 (<Q1), and when the bucket pin distance is D3 or more and less than D4, the power generation amount per unit time is Q3 (<Q2). . When the bucket pin distance is less than D1 or greater than D4, the bucket pin position is outside the actual work area WA, and thus the power generation amount per unit time is zero.

  Moreover, in the above-described embodiment, the pre-load boost necessity determination unit 32 gradually reduces the power generation amount per unit time as the bucket pin distance increases. However, the pre-load boost necessity determination unit 32 may decrease the power generation amount per unit time linearly or nonlinearly as the bucket pin distance increases.

  Moreover, in the above-mentioned Example, the pre-load boost necessity determination part 32 reduces the electric power generation amount per unit time, so that the bucket pin distance is large. However, the pre-load boost necessity determination unit 32 may reduce the power generation amount per unit time as the height of the bucket pin position with respect to the ground surface of the shovel increases, and the depth of the bucket pin position with respect to the ground surface of the shovel You may reduce the electric power generation amount per unit time, so that it is large. Further, the power generation amount per unit time may be reduced as the reach of the attachment is longer, that is, as the excavation attachment is extended. Thus, when the pre-load boost necessity determination unit 32 executes the pre-load boost function, the greater the bucket pin distance, or the greater the height or depth of the bucket pin position with respect to the ground surface of the shovel, Or you may reduce the magnitude | size of the increase in the supercharging pressure implement | achieved by execution of the boost function before load, so that the reach of an attachment is long.

  Further, the pre-load boost necessity determination unit 32 may reduce the power generation amount per unit time as the bucket pin position moves away from the reference region. Note that the reference area is a partial area in the actual work area WA when the increase in the boost pressure realized by executing the pre-load boost function is maximized, for example. In the present embodiment, this is a partial area in the actual work area WA when the power generation amount per unit time realized by the execution of the pre-load boost function is maximized. In the actual work area WA, for example, the farther the bucket pin position is from the reference area, that is, the closer to the boundary of the actual work area WA, the closer the power generation amount per unit time is to zero, and the closer the bucket pin position is to the reference area. That is, the power generation amount per unit time approaches the maximum value as the distance from the boundary of the actual work area WA increases.

  With this configuration, the controller 30 can suppress a sudden change in the contents of the boom raising operation between the case where the bucket pin position is inside and near the boundary of the actual work area.

  Next, a process in which the controller 30 determines whether or not to execute the pre-load boost function (hereinafter referred to as “pre-load boost necessity determination process”) will be described with reference to FIG. FIG. 7 is a flowchart illustrating an example of a pre-load boost necessity determination process. The controller 30 executes this pre-load boost necessity determination process every time the boom raising operation is started. In the present embodiment, the controller 30 executes this pre-load boost necessity determination process every time the boom operation lever is operated by a predetermined amount or more in the upward direction from the neutral position.

  First, the controller 30 derives an end attachment position (step ST1). In the present embodiment, the attachment position acquisition unit 31 of the controller 30 derives the bucket pin position as the end attachment position based on the outputs of the boom angle sensor S1 and the arm angle sensor S2. Note that the end attachment position may be a position on the end attachment other than the position of the pin (for example, bucket pin position) connecting the end attachment (for example, bucket 6) and the arm 5.

  Further, the controller 30 acquires information related to the actual work area (step ST2). In the present embodiment, the pre-load boost necessity determination unit 32 of the controller 30 acquires information regarding the actual work area stored in the storage device or the like of the controller 30. Specifically, the depth D, height H, proximity C, and distance F that define the actual work area WA as shown in FIG. 5 are read from the storage device. Note that step ST1 and step ST2 are out of order and may be executed simultaneously.

  Thereafter, the controller 30 determines whether the end attachment position is within the actual work area (step ST3). In the present embodiment, the pre-load boost necessity determination unit 32 determines that the bucket pin position is within the actual work area based on the information related to the actual work area read from the storage device and the bucket pin position derived by the attachment position acquisition unit 31. It is determined whether or not there is.

  When it is determined that the bucket pin position as the end attachment position is not within the actual work area (NO in step ST3), the pre-load boost necessity determination unit 32 determines that the pre-load boost function is not necessary, This pre-load boost necessity determination process is terminated without executing the pre-load boost function.

  On the other hand, when it is determined that the bucket pin position as the end attachment position is within the actual work area (YES in step ST3), the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed. Then, the pre-load boost function is executed (step ST4). In this embodiment, the pre-load boost necessity determination unit 32 outputs a power generation command to the inverter 18 to start a short-time power generation by the motor generator 12 to positively increase the load on the engine 11.

  With this configuration, when the bucket pin position as the end attachment position is within the actual work area, the controller 30 increases the supercharging pressure before a sudden increase in the hydraulic load associated with the boom raising operation occurs. Therefore, even when the hydraulic load suddenly increases, the engine output can be increased smoothly while maintaining the rotation speed of the engine 11 substantially constant, and the responsiveness at the start of the boom raising operation can be improved.

  Further, when the bucket pin position as the end attachment position is not within the actual work area, the controller 30 does not actively increase the load of the engine 11 even when the boom raising operation is started. . Therefore, it is possible to prevent an unnecessarily increase in the responsiveness of the boom raising operation. Further, since the power generation by the motor generator 12 is not started, it is possible to prevent the fuel consumption from increasing unnecessarily.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the pre-load boost necessity determination unit 32 determines whether the pre-load boost function needs to be executed based on the bucket pin position. However, the present invention is not limited to this configuration. For example, the pre-load boost necessity determination unit 32 may determine whether or not to execute the pre-load boost function based on whether or not the arm pin position is within a predetermined corresponding actual work area. The pre-load boost necessity determination unit 32 may determine whether the pre-load boost function needs to be executed based on whether or not the bucket tip position is within a predetermined corresponding actual work area.

  Further, in the above-described embodiment, the pre-load boost necessity determination unit 32 determines whether or not the pre-load boost function is necessary when the boom raising operation is performed. However, the present invention is not limited to this configuration. For example, the pre-load boost necessity determination unit 32 may determine whether the pre-load boost function needs to be performed when an operation other than the boom raising operation such as a boom lowering operation or an arm closing operation is performed. . In this case, “various operation amounts” that are outputs of the pressure sensor 29 in FIG. 3 include operation amounts of a boom operation lever, an arm operation lever, a bucket operation lever, and the like.

  In the above-described embodiment, the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed when it is determined that the bucket pin position P3 is within the actual work area. However, the present invention is not limited to this configuration. For example, the pre-load boost necessity determination unit 32 may determine that it is not necessary to execute the pre-load boost function when it is determined that the bucket pin position P3 is in the non-actual work area. The “non-actual work area” is set as a partial area within the area where the bucket pin position can be reached, which is set around the excavator, similarly to the “real work area”. The actual work area is in principle closer to the excavator than the non-actual work area. Further, information regarding the non-actual work area may be stored in advance in a storage device or the like of the controller 30, and may be adjustable via an input device or the like. When a non-actual work area is set, the setting of the actual work area is omitted. This is because the non-actual work area and the actual work area have a complementary relationship. Further, the non-actual work area may be adjacent to at least one of the upper, lower and far sides of the actual work area when viewed from the excavator. In this embodiment, the non-actual work area is adjacent to the actual work area WA above (+ Z direction in FIG. 5), below (−Z direction), and far (+ X direction) as shown in FIG. Further, the partial area closer to the turning axis SX than the actual work area may be a non-actual work area. This is because, for example, when the bucket 6 is in front of the cabin with the arm 5 closed to the maximum, it is estimated that the need for a quick boom raising operation is low.

  A plurality of actual work areas may be set. For example, the first actual work area for executing the first pre-load boost function for realizing a relatively high boost pressure and the second pre-load boost function for realizing a relatively low boost pressure are executed. A second actual work area may be set. In this case, the pre-load boost necessity determination unit 32 determines that the first pre-load boost function needs to be executed when it is determined that the bucket pin position P3 is within the first actual work area, and the bucket pin position When it is determined that P3 is in the second actual work area, it is determined that the second pre-load boost function needs to be executed.

  In the above-described embodiment, the actual work area is set as a rectangular area, but may be defined using a curve.

  Further, in the above-described embodiment, the pre-load boost function positively increases the load of the engine 11 and thus the supercharging pressure by executing short-time power generation by the motor generator 12 before the hydraulic load increases. However, the present invention is not limited to this configuration.

  For example, when the turbocharger of the engine 11 is a variable nozzle turbo, the pre-load boost function is a nozzle vane that controls the flow rate of exhaust gas flowing from the exhaust port of the engine 11 to the turbine blades before the hydraulic load increases. The supercharging pressure may be positively increased by temporarily reducing the nozzle opening. Specifically, the supercharging pressure may be positively increased by decreasing the nozzle opening degree of the nozzle vanes and increasing the rotational speed of the turbine blade and thus the rotational speed of the compressor blade.

  Alternatively, the pre-load boost function may positively increase the load of the engine 11 and thus the supercharging pressure by temporarily increasing the discharge amount of the main pump 14 before the hydraulic load increases. Specifically, the main pump 14 has a predetermined discharge amount that is larger than the discharge amount (discharge amount corresponding to the lever operation amount) determined using various flow rate control methods such as negative control control, positive control control, and load sensing control. , The load on the engine 11 and thus the supercharging pressure may be positively increased.

  Alternatively, the pre-load boost function positively increases the load on the engine 11 and thus the supercharging pressure by temporarily increasing the discharge amount of another hydraulic pump connected to the engine 11 before the hydraulic load increases. You may let them. Specifically, the load on the engine 11 and thus the supercharging pressure may be positively increased by increasing the discharge amount of another hydraulic pump having higher responsiveness than the main pump 14. Note that the hydraulic oil discharged from another hydraulic pump may be discharged to the hydraulic oil tank as it is.

  Alternatively, the pre-load boost function may positively increase the load of the engine 11 and thus the supercharging pressure by temporarily increasing the discharge pressure of the main pump 14 before the hydraulic load increases. Specifically, the load on the engine 11 and the supercharging pressure are positively increased by controlling the relief valve, the switching valve, etc. arranged on the discharge side of the main pump 14 to increase the discharge pressure of the main pump 14. May be. Alternatively, the hydraulic oil accumulated in the accumulator may be supplied to the discharge side of the main pump 14 to increase the discharge pressure of the main pump 14 to positively increase the load on the engine 11 and thus the supercharging pressure.

  Next, another example of the actual work area will be described with reference to FIG. FIG. 8 is a side view of the excavator, and shows an actual work area WA1, an actual work area WA2, and an actual work area WA3 set on the XZ plane. The actual work area WA1 surrounded by a dotted line is an area that is referred to when the pre-load boost necessity determination unit 32 determines whether or not to execute the pre-load boost function when a boom raising operation is performed, This corresponds to the actual work area WA in FIG. The actual work area WA2 surrounded by the alternate long and short dash line is an area that is referred to when the pre-load boost necessity determination unit 32 determines whether to execute the pre-load boost function when the arm closing operation is performed. . The actual work area WA3 surrounded by the two-dot chain line is an area that is referred to when the pre-load boost necessity determination unit 32 determines whether to execute the pre-load boost function when the bucket closing operation is performed. is there.

  In the present embodiment, the actual work area WA2 is set at a position farther from the turning axis SX than the actual work area WA1. For this reason, the pre-load boost necessity determination unit 32 differs from the determination result when the boom raising operation is performed when the attachment position acquisition unit 31 derives the bucket pin position P3d when the arm closing operation is performed. Bring the judgment result. That is, it is determined that the bucket pin position is within the actual work area WA2, and it is determined that the pre-load boost function needs to be executed.

  The actual work area WA3 is set to include the actual work area WA1 and the actual work area WA2. Therefore, when the bucket closing operation is performed, the pre-load boost necessity determination unit 32 may bring a determination result different from the determination result when the boom raising operation or the arm closing operation is performed. That is, even if it is determined that the bucket pin position is not in any of the actual work area WA1 and the actual work area WA2, it is determined that the bucket pin position is in the actual work area WA3 and the pre-load boost function is executed. There are times when it is determined that it is necessary. For example, the actual work area WA3 may be set as an area including the bucket pin position P3c so that a pre-load boost is executed when a bucket closing operation is performed during deep excavation. In this case, the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed when the attachment position acquisition unit 31 derives the bucket pin position P3c.

  Next, with reference to FIG. 9, a time transition of a plurality of physical quantities when a boom raising operation is performed after a combined operation including an arm closing operation and a bucket closing operation is described. FIG. 9A to FIG. 9F are time charts showing temporal transitions of the lever operation amount, the power generation amount, the hydraulic load, the fuel consumption amount, the supercharging pressure, and the engine speed. The solid line in FIG. 9 shows the temporal transition of each physical quantity when the pre-load boost is executed, and the alternate long and short dash line shows the temporal transition of each physical quantity when the pre-load boost is not executed. For the sake of clarity, FIG. 9 shows the solid line and the alternate long and short dash line so as not to overlap each other. However, the portion where the solid line and the alternate long and short dash line are parallel means that both follow the same locus.

  As shown in FIG. 9A, the shovel operator operates the arm operation lever in the closing direction at time t1, operates in the neutral direction at time t6, and operates the boom operation lever in the raising direction at time t7. . In addition, the operator operates the bucket operation lever in the closing direction after starting the operation in the closing direction of the arm operation lever, and moves the bucket operation lever to the neutral position at almost the same timing as returning the arm operation lever to the neutral position. Return to. In FIG. 9A, the change in the lever operation amount of the bucket operation lever is not shown for the sake of clarity.

  First, a change in each physical quantity when the pre-load boost is not executed will be described with reference to a transition indicated by a one-dot chain line.

  When the arm closing operation is started at time t1, the lever operation amount (for example, lever operation angle) of the arm operation lever increases from time t1 to time t2. At time t2, the lever operation amount reaches the maximum value.

  As shown in FIG. 9C, the hydraulic load of the main pump 14 increases as the discharge pressure of the main pump 14 increases as the excavation reaction force acting on the arm 5 increases. The engine load increases as the hydraulic load increases. As a result, as indicated by the alternate long and short dash line in FIG. 9 (f), the engine speed greatly decreases after the time t2.

  When the controller 30 detects that the engine load has increased and the engine speed has deviated from the predetermined speed Nc, the controller 30 increases the fuel injection amount of the engine 11. As a result, the fuel consumption of the engine 11 increases at time t3 as indicated by the alternate long and short dash line in FIG. When the fuel injection amount increases for a while, the engine speed starts to increase as indicated by the one-dot chain line in FIG.

  When the engine speed starts to increase, the supercharging pressure starts to increase at time t4, as indicated by the alternate long and short dash line in FIG. As a result, the controller 30 can increase the combustion efficiency of the engine 11 and increase the output of the engine 11 efficiently.

  Thereafter, the controller 30 attempts to maintain the engine speed at a predetermined speed Nc by isochronous control. However, since the fuel consumption has increased, the engine speed does not immediately stabilize even when the engine speed reaches the predetermined speed Nc, and continues to increase beyond the predetermined speed Nc. After a while after the fuel consumption is reduced, the engine speed stops increasing, and at time t5, the engine speed starts to decrease. Thus, the engine speed changes with a delay in the change in the fuel injection amount. Therefore, even if the increase in the fuel injection amount is stopped when the engine speed reaches the predetermined speed Nc, the engine speed exceeds the predetermined speed Nc and overshoots.

  Thereafter, at time t6, the operator starts returning the arm operation lever to the neutral position in order to stop the closing operation of the arm 5. As a result, the excavation reaction force decreases, and the hydraulic load on the main pump 14 decreases as shown in FIG. As the hydraulic load decreases, the engine load also decreases, so the fuel consumption also decreases as shown in FIG. 9D, and the supercharging pressure also decreases as shown in FIG. 9E.

  Thereafter, at time t7, the operator operates the boom operation lever in the raising direction in order to perform the raising operation of the boom 4. The lever operation amount of the boom operation lever starts to increase at time t7 as shown in FIG. 9A, and reaches a maximum value at time t8.

  The hydraulic load, which has been reduced when the operation of the arm 5 stops, starts to rise again due to the operation of the boom 4 after a while after the time t7. Specifically, the discharge pressure of the main pump 14 increases due to the load applied to the boom 4, and the hydraulic load of the main pump 14 begins to increase around time t8 as shown in FIG. 9C. The engine load also increases with the hydraulic load. As a result, as indicated by the alternate long and short dash line in FIG. 9F, the engine speed decreases after the time t8.

  When the controller 30 detects that the engine load increases and the engine speed deviates from the predetermined speed Nc, the controller 30 increases the fuel injection amount of the engine 11. As a result, the fuel consumption of the engine 11 increases at time t9 as indicated by the alternate long and short dash line in FIG. When the fuel injection amount increases for a while, the engine speed starts to increase as indicated by the one-dot chain line in FIG.

  When the engine speed starts to increase, the supercharging pressure starts to increase at time t10, as shown by the one-dot chain line in FIG. As a result, the controller 30 can increase the combustion efficiency of the engine 11 and increase the output of the engine 11 efficiently.

  Thereafter, the controller 30 attempts to maintain the engine speed at a predetermined speed Nc by isochronous control. However, since the fuel consumption has increased, the engine speed does not immediately stabilize even when the engine speed reaches the predetermined speed Nc, and continues to increase beyond the predetermined speed Nc. After a while after the fuel consumption is reduced, the engine speed stops increasing, and at time t11, the engine speed starts to decrease. Thus, the engine speed changes with a delay in the change in the fuel injection amount. Therefore, even if the increase in the fuel injection amount is stopped when the engine speed reaches the predetermined speed Nc, the engine speed exceeds the predetermined speed Nc and overshoots.

  As described above, when the pre-load boost is not executed, the engine speed greatly decreases as the hydraulic load increases, and the fuel consumption greatly increases in order to recover it.

  Therefore, in this embodiment, the pre-load boost is executed to suppress the engine speed drop, and the fuel consumption used for recovering the engine speed is reduced as much as possible.

  Specifically, when the pre-load boost necessity determination unit 32 detects that the arm operation lever is operated at time t1, the bucket pin position P3 output by the attachment position acquisition unit 31 is set to the actual work area WA2 (FIG. 8). See :).

  When it is determined that the bucket pin position P3 is within the actual work area WA2, the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed, and immediately causes the motor generator 12 to perform a power generation operation. Let The time for which the motor generator 12 is operated to generate electricity may be a short time of about 0.1 seconds, for example. Since the motor generator 12 is driven by the engine 11 to perform a power generation operation, a load is applied to the engine 11 by the power generation operation. As a result, as indicated by the solid line in FIG. 9 (f), the engine speed starts to decrease from time t1.

  When the engine speed starts to decrease, the controller 30 increases the engine speed by increasing the fuel injection amount by isochronous control. However, the time during which the motor generator 12 is operated for power generation is short, the power generation amount is set small, and the fuel injection amount is immediately increased. Therefore, the engine speed starts to decrease at time t1 as shown by the solid line in FIG. 9 (f), but immediately starts to increase and returns to the predetermined speed Nc again. Since the engine speed returns to the predetermined speed Nc, as shown by the solid line in FIG. 9D, the increased fuel consumption amount also returns.

  Thus, the controller 30 applies a load to the engine 11 by causing the motor generator 12 to perform a power generation operation only for a short time in accordance with the closing operation of the arm operation lever. As a result, as shown by the solid line in FIG. 9 (e), the increase of the supercharging pressure can be started at time t2 when the hydraulic load starts to increase. That is, the motor generator 12 is caused to perform a power generation operation by predicting an increase in the hydraulic load of the main pump 14 based on the lever operation amount of the arm operation lever. Thereby, before the hydraulic load actually increases, the load on the engine 11 can be applied by increasing the power generation load of the motor generator 12. The reason why the load is applied to the engine 11 is that the boost pressure of the engine 11 is raised in advance prior to the increase of the hydraulic load so that the increase of the engine load due to the increase of the hydraulic load can be quickly dealt with.

  After the time t2, the hydraulic load increases and the engine load also increases. Then, the controller 30 outputs a fuel injection amount increase command at time t3. As a result, as shown in FIG. 9D, the fuel consumption gradually increases. The increase in fuel consumption at this time corresponds to an increase in hydraulic load. Since the engine speed has already reached the predetermined speed Nc, it is not necessary to consume fuel in order to increase the engine speed. At time t3, since the boost pressure has already increased to a predetermined value, the engine 11 can efficiently increase the output even if the hydraulic load increases, and can suppress an increase in fuel consumption. This effect is shown as the difference between the alternate long and short dash line (transition when the pre-load boost is not executed) and the solid line (transition when the pre-load boost is executed) between time t3 and time t5 in FIG. 9 (d). ing.

  Thereafter, at time t6, the operator starts returning the arm operation lever to the neutral position in order to stop the closing operation of the arm 5. As a result, the excavation reaction force decreases and the hydraulic load on the main pump 14 also decreases. As the hydraulic load decreases, the engine load also decreases, so the fuel consumption decreases as shown by the solid line in FIG. 9D, and the supercharging pressure also decreases as shown by the solid line in FIG. 9E. .

  A decrease in hydraulic load can also occur when the arm closing operation continues. For example, the excavation reaction force decreases when the arm 5 tries to escape from the ground by the closing operation of the arm 5, and the excavation reaction force disappears after the arm 5 comes out into the air.

  Thereafter, at time t7, the operator operates the boom operation lever in the raising direction in order to perform the raising operation of the boom 4. As shown by the solid line in FIG. 9A, the lever operation amount of the boom operation lever starts to increase at time t7 and reaches a maximum value at time t8.

  When the pre-load boost necessity determination unit 32 detects that the boom operation lever is operated in the raising direction, the bucket pin position P3 output by the attachment position acquisition unit 31 is within the actual work area WA1 (see FIG. 8). It is determined whether or not there is. In the present embodiment, the pre-load boost necessity determination unit 32 determines that the bucket pin position P3 is detected when it is detected that the boom operation lever is operated in the up direction regardless of whether the arm closing operation is continued. It is determined whether it is in the actual work area WA1 (see FIG. 8). This is because, as described above, the hydraulic load can be lowered even when the arm closing operation is continued. Accordingly, not only when the boom raising operation is performed alone, but also when the combined operation including the arm closing operation and the boom raising operation is performed, the pre-load boost can be executed. The same applies to the case where a combined operation including a bucket closing operation and a boom raising operation is performed. However, the pre-load boost necessity determination unit 32 may omit this determination when the discharge pressure of the main pump 14 is equal to or higher than a predetermined pressure. That is, the pre-load boost may be omitted. This is because it can be estimated that the supercharging pressure is already sufficiently high.

  When it is determined that the bucket pin position P3 is within the actual work area WA1, the pre-load boost necessity determination unit 32 determines that the pre-load boost function needs to be executed, and immediately causes the motor generator 12 to perform a power generation operation. Let The time for which the motor generator 12 is operated to generate electricity may be a short time of about 0.1 seconds, for example. Since the motor generator 12 is driven by the engine 11 to perform a power generation operation, a load is applied to the engine 11 by the power generation operation. As a result, as indicated by a solid line in FIG. 9F, the engine speed starts to decrease from time t7.

  When the engine speed starts to decrease, the controller 30 controls the fuel injection amount by isochronous control to increase the engine speed. In this embodiment, the controller 30 stops the decrease in fuel consumption as shown by the solid line in FIG. The fuel consumption may be increased as necessary. However, the time for which the motor generator 12 is operated to generate electricity is short, and the amount of power generation is set small. Therefore, the engine speed starts to decrease at time t7 as shown by the solid line in FIG. 9 (f), but immediately starts to increase and again returns to the predetermined speed Nc. Since the engine speed returns to the predetermined speed Nc, the reduction in fuel consumption is resumed as shown by the solid line in FIG.

  In this way, the controller 30 applies a load to the engine 11 by causing the motor generator 12 to perform a power generation operation for a short time according to the raising operation of the boom operation lever, as in the case where the arm closing operation is performed. As a result, as shown by the solid line in FIG. 9 (e), the increase of the supercharging pressure can be started before the hydraulic load starts to increase. That is, the motor generator 12 is caused to perform a power generation operation by predicting an increase in the hydraulic load of the main pump 14 based on the lever operation amount of the boom operation lever. Thereby, before the hydraulic load actually increases, the power generation load of the motor generator 12 can be increased and the load can be applied to the engine 11. The reason why the load is applied to the engine 11 is that the boost pressure of the engine 11 is raised in advance prior to the increase of the hydraulic load so that the increase of the engine load due to the increase of the hydraulic load can be quickly dealt with.

  After the time t8, the hydraulic load increases and the engine load also increases. Then, the controller 30 outputs a fuel injection amount increase command at time t9. As a result, the fuel consumption gradually increases as shown by the solid line in FIG. The increase in fuel consumption at this time corresponds to an increase in hydraulic load. That is, since the engine speed has already reached the predetermined speed Nc, it is not necessary to consume fuel in order to increase the engine speed. At time t9, since the boost pressure has already increased to a predetermined value, the engine 11 can efficiently increase the output even if the hydraulic load increases, and can suppress an increase in fuel consumption. This effect is shown as the difference between the alternate long and short dash line (transition when the pre-load boost is not executed) and the solid line (transition when the pre-load boost is executed) between time t9 and time t11 in FIG. 9 (d). ing.

  As described above, the controller 30 predicts an increase in the hydraulic load based on the operation of the operation lever, and increases the power generation load of the motor generator 12 before the hydraulic load increases. As a result, when the engine load actually increases, the controller 30 can set the engine speed to the predetermined speed Nc and increase the supercharging pressure of the engine 11. That is, it is possible to prevent the supercharging pressure of the engine 11 from becoming lower than a predetermined value. Therefore, the engine speed is not greatly reduced, and fuel for increasing the engine speed is not consumed. Normally, the power generation load of the motor generator 12 is increased when the charging rate of the capacitor 19 is decreased. In this embodiment, however, the power generation amount of the motor generator 12 is obtained even when there is no power generation request from the electric load. Is increased to control the drive of the engine 11.

  The description related to FIG. 9 is applied when the boom raising operation is performed after the combined operation including the arm closing operation and the bucket closing operation is performed, but the boom raising operation is performed after the arm closing operation is performed alone. It can also be applied to Further, the present invention can be applied to a case where the boom raising operation is performed after the bucket closing operation is performed alone.

  This application claims priority based on Japanese Patent Application No. 2014-266378 filed on Dec. 26, 2014, the entire contents of which are incorporated herein by reference.

  DESCRIPTION OF SYMBOLS 1 ... Lower traveling body 2A, 2B ... Traveling hydraulic motor 2 ... Turning mechanism 3 ... Upper turning body 4 ... Boom 5 ... Arm 6 ... Bucket 7 ... Boom Cylinder 8 ... Arm cylinder 9 ... Bucket cylinder 11 ... Engine 12 ... Motor generator 13 ... Reduction gear 14 ... Main pump 15 ... Pilot pump 16 ... High pressure hydraulic line DESCRIPTION OF SYMBOLS 17 ... Control valve 18 ... Inverter 19 ... Capacitor 19a ... Buck-boost converter 19b ... DC bus 20 ... Inverter 21 ... Electric motor for turning 21A ... Output shaft 22 ....・ Resolver 23 ... Mechanical brake 24 ... Swivel reducer 25 ... Pilot line 26 ... Operating device 27, 28 ... Hydraulic Line 29 ... Pressure sensor 30 ... Controller 31 ... Attachment position acquisition unit 32 ... Pre-load boost necessity determination unit 120 ... Power storage device S1 ... Boom angle sensor S2 ... Arm angle Sensor S3 ... Bucket angle sensor

Claims (10)

An attachment including a work body;
A diesel engine with a turbocharger;
A hydraulic pump coupled to the turbocharged diesel engine;
A controller that performs a pre-load boost function that increases a supercharging pressure of the supercharger before a hydraulic load of the hydraulic pump increases;
The region where the predetermined part of the attachment can be reached includes a partial region where the pre-load boost function is executed when the work body is operated, and the pre-load boost function is executed when the work body is operated Including partial areas that are not
Excavator. The controller reduces the amount of increase in supercharging pressure realized by executing the pre-load boost function as the position of the predetermined part of the attachment is further away from the reference position or reference region.
The excavator according to claim 1. The controller reduces the magnitude of the increase in the load of the turbocharged diesel engine realized by executing the pre-load boost function as the position of the predetermined part of the attachment is further away from the reference position or the reference region.
The excavator according to claim 1. The controller increases the load as the height of the predetermined portion of the attachment is higher than the reference position, or as the depth of the predetermined portion of the attachment is deeper than the reference position, or as the reach of the attachment is longer. Reduce the amount of increase in boost pressure realized by executing the pre-boost function,
The shovel according to claim 2. A motor generator coupled to the turbocharged diesel engine;
The controller increases the supercharging pressure of the supercharger by increasing the amount of power generated by the motor generator before the hydraulic load of the hydraulic pump increases.
The excavator according to claim 1. A posture detecting device for detecting the posture of the attachment;
The controller acquires information on a position of a predetermined part of the attachment based on an output of the posture detection device;
The excavator according to claim 1. The partial area where the pre-load boost function is not executed when the work body is operated is above, below and far from the partial area where the pre-load boost function is executed when the work body is operated. Adjacent to at least one of the
The excavator according to claim 1. The partial area where the pre-load boost function is executed when the work body is operated is closer to the excavator than the partial area where the pre-load boost function is not executed when the work body is operated,
The excavator according to claim 1. In a portion closer to the excavator than a partial region where the pre-load boost function is executed when the work body is operated, another portion where the pre-load boost function is not executed when the work body is operated There is an area,
The excavator according to claim 8. When the working body is operated, when a boom raising operation is performed, an arm closing operation is performed, or a bucket closing operation is performed.
The excavator according to claim 1.

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